Soil Nitrate-Nitrogen Sampling

Vast amounts of nitrogen (N) exist in our soils in many different forms, but only nitrate (NO3–) and ammonium (NH4+) can be taken up via the plant roots. Most of the nitrogen in the soil is in the organic form, which much be broken down by micro-organisms to become plant available. Mineralization is the process […]

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What does 2023’s Weather Tell Us about Anticipated Soil Nitrogen Supply?

A sidedress applicator injecting nitrogen fertilizer in-season in corn.

Summary Background Throughout the growing season, microbes within the soil break down organic nitrogen contained in soil organic matter and release it as plant-available ammonium.  This process is known as nitrogen mineralization. Nitrogen mineralization is favoured by warm soil temperatures with adequate soil moisture and aeration.  Excess moisture can slow mineralization or increase the potential […]

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Verifying a Pre-Sidedress Soil Nitrate Threshold Test for Evaluating Nitrogen Top-Up Needs

Purpose: Pre-sidedress soil nitrate test (PSNT) provide a means of estimating soil nitrogen supply, and can aid producers in fine-tuning their nitrogen application rates for corn. One drawback of current soil nitrate tests is that they are only calibrated for situations where all of the nitrogen being measured has come from soil mineralization, that is […]

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